Rotary Roller Reamer

Abstract

A bore hole rotary reamer ( 1 ) includes a body ( 2 ) having cutters ( 4 ) contained in respective recesses ( 3 ) formed in the body ( 2 ). Each cutter ( 4 ) is rotatably mounted by one or more respective spindles ( 5 ). A bearing region ( 10 ) is formed by an inner bearing surface ( 11 ) rotatable on an outer surface of the spindle ( 5 ). At least one annular seal ( 12 ) about the spindle ( 5 ) prevents ingress of contaminant to the bearing region (b 10). A circumferential void ( 13 ) is formed between the inner bearing surface ( 11 ) and the outer bearing surface of the spindle ( 5 ) adjacent the seal ( 12 ). At least one passageway ( 17 ) extends in an axial direction of the spindle ( 5 ) to the circumferential void ( 13 ) and a piston ( 19 ) movable in the passageway ( 17 ) in response to supply of pressure to an outer side ( 19 a ) of the piston ( 19 ) from the environment which surrounds the reamer ( 1 ). The piston ( 19 ) transfers pressure to fluid in the cylindrical passage ( 17 ) on an inner side of the piston ( 19 ) to supply pressure to the circumferential void ( 13 ) and thereby to the seal ( 12 ) that is substantially determined by the pressure of the environment surrounding the reamer ( 1 ).

1 . A bore hole rotary reamer comprising a body having cutters contained in respective recesses formed in the body, each cutter being rotatably mounted by one or more respective spindles and a bearing region formed by an inner bearing surface rotatable on an outer surface of the spindle; at least one annular seal about the spindle to prevent ingress of contaminant to the bearing region; a circumferential void formed between the inner bearing surface and the outer bearing surface of the spindle adjacent said seal; at least one passageway extending in an axial direction of the spindle to said circumferential void; and a piston movable in said passageway in response to supply of pressure to an outer side of said piston from the environment which surrounds the reamer, whereby the piston transfers pressure to fluid in said cylindrical passage on an inner side of said piston to supply pressure to said circumferential void and thereby to said seal that is substantially determined by the pressure of the environment surrounding the reamer. 
   
   
       2 . A bore hole rotary reamer according to  claim 1 , wherein the pressure that is applied to said seals via said apertures is substantially the pressure of the environment surrounding the reamer. 
   
   
       3 . A bore hole rotary reamer according to  claim 1 , wherein said piston is freely floatable in said passageway to impart the pressure supplied from the environment which surrounds the reamer to fluid on said inner side of the piston. 
   
   
       4 . A bore hole rotary reamer according to  claim 1 , wherein, in use, the fluid on said inner side of said piston is a lubricant and said piston impels a flow of lubricant to said circumferential void to apply pressure to said seal. 
   
   
       5 . A bore hole rotary reamer according to  claim 1 , wherein said passageway includes a cylindrical portion extending axially of the spindle containing said piston and an aperture communicating between said cylindrical portion and said circumferential void. 
   
   
       6 . A bore hole rotary reamer according to  claim 1 , comprising an annular seal at each end of said bearing region each annular seal having an adjacent circumferential void and one or more of said passageway extending to each circumferential void. 
   
   
       7 . A bore hole rotary reamer according to  claim 6 , wherein a separate passageway respectively extends to each of said circumferential voids and each passageway includes one said movable piston. 
   
   
       8 . A bore hole rotary reamer according to  claim 6 , wherein each cutter is rotatably mounted on a central region of a respective spindle and said bearing region is formed by an inner surface of the cutter rotatable on an outer surface of the spindle. 
   
   
       9 . A bore hole rotary reamer according to  claim 8 , wherein a separate passageway respectively extends between each of said circumferential voids and a corresponding cuter end of the respective spindle. 
   
   
       10 . A bore hole rotary reamer according to  claim 1 , wherein said circumferential voids are formed by grooves on the outer surface of the spindle. 
   
   
       11 . A bore hole rotary reamer according to  claim 1 , wherein said circumferential voids are formed by grooves in said inner bearing surface. 
   
   
       12 . A bore hole rotary reamer comprising a body having cutters contained in respective recesses formed in the body, each cutter being rotatably mounted in a central region of a respective spindle and having a bearing region formed by an inner bearing surface of the cutter rotatable on an outer surface of the spindle; annular seals interposed between the cutter and spindle at each end of the bearing region to prevent ingress of contaminant; a circumferential void formed between the inner bearing surface and the outer bearing surface of the spindle at each end of the bearing region adjacent each said seal, at least one cylindrical passage extending in an axial direction in each spindle, respective apertures extending from said cylindrical passage to each of said circumferential voids; and a piston freely floatable in said cylindrical passage between an outer end of said cylindrical passage and said apertures, an outer end of said piston being supplied with pressure substantially equal to the pressure of the environment which surrounds the reamer, whereby the piston imparts that pressure to lubricant when contained in said cylindrical passage and impels a flow of said lubricant to said circumferential voids to apply a lubricant pressure to each of said seals that is substantially the pressure of the environment surrounding the reamer. 
   
   
       13 . (canceled)